Definition
An approach lighting system installed at the approach end of certain runways, consisting of a shortened configuration of steady-burning white lights extending outward from the runway threshold along the extended runway centerline, combined with sequenced flashing lights that fire in rapid succession toward the threshold to give the pilot a strong directional cue during the final segment of an instrument approach.
Plain English
A row of lights leading up to the runway, with extra flashing lights that pulse one after another toward the runway. The flashing pattern points the pilot straight at the touchdown end so they can line up and land in poor visibility.
Context Anchor
Seen on instrument approach charts and in airport lighting information for a runway.
Derivation
Simplified means a reduced version of a fuller system. Short refers to the shorter overall length compared with standard approach light systems. Sequenced Flashers describes lights that fire in order, one after the next, rather than all at once — the visual effect is a bright pulse racing toward the runway.
Why Pilots Care
Provides positive runway identification and alignment cues in low visibility when a full-length approach light system cannot be installed due to terrain or space limits.
Grounding Statement
Picture a row of lights before the runway, with flashes moving toward the runway to help you pick it out ahead.
Intuition Check
“Simplified” and “short” do not mean casual or optional here. They describe a specific FAA approach light system layout that is smaller than some full approach lighting systems.
Example Sentence 1
The approach plate showed SSALF serving Runway 27, so the crew briefed that they would look for the sequenced flashers pulsing toward the threshold once they descended below the cloud base.
Example Sentence 2
Because the runway had limited overrun area, the airport installed SSALF rather than a full ALSF system.